Catalyst components for the polymerization of olefins

ABSTRACT

Catalyst component for the polymerization of olefins comprising Mg, Ti and an electron donor compound of the following formula (I) 
                         
In which
 
R to R 4  groups, equal to or different from each other, are hydrogen, halogen or C 1 -C 15  hydrocarbon groups, optionally containing an heteroatom selected from halogen, P, S, N and Si, which may be linked to form a saturated or unsaturated mono or polycycle and R 5  groups are selected from C 1 -C 15  hydrocarbon groups optionally containing an heteroatom selected from halogen, P, S, N and Si.

This application is the U.S. National Phase of PCT International Application PCT/EP2012/070071, filed Oct. 10, 2012, claiming priority of European Patent Application No. 11185711.6, filed Oct. 19, 2011, and the benefit under 35 U.S.C. 119(e) of U.S. Provisional Application No. 61/549,123 filed Oct. 19, 2011, the contents of which are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to catalyst components for the polymerization of olefins, in particular propylene, comprising a Mg dihalide based support on which are supported Ti atoms and at least an electron donor compound selected from a specific class. The present invention further relates to the catalysts obtained from said components and to their use in processes for the polymerization of olefins in particular propylene.

BACKGROUND OF THE INVENTION

Catalyst components of the Ziegler-Natta type for the stereospecific polymerization of olefins are widely known in the art. The latest developed catalysts for propylene polymerization comprise a solid catalyst component, constituted by a magnesium dihalide on which are supported a titanium compound and an internal electron donor compound, used in combination with an Al-alkyl compound and often with an external donor which is needed in order to obtain higher isotacticity. One of the preferred classes of internal donors is constituted by the esters of aromatic carboxylic acids such as benzoates and phthalates this latter being the most used in view of their excellent performances. The phthalates are used as internal donors in combination with alkylalkoxysilanes as external donor. This catalyst system is capable of giving good performances in terms of activity, and propylene polymers with high isotacticity and xylene insolubility endowed with an intermediate molecular weight distribution.

As the use of some phthalates has been recently addressed as involving potential toxicity problems, the interest in exploration of alternative classes of donor has increased.

U.S. Pat. No. 5,041,403 discloses alkoxyesters of formula (R¹O)_(i)(R²O)_(j)(R³O)_(k)—Z—COOR⁴ (I) wherein R¹, R², R³ and R⁴ are an aliphatic, alicyclic, aromatic, polycyclic or heterocyclic compound group, Z is an aliphatic or alicyclic hydrocarbon group in which hydrogen may be substituted with an aromatic or polycyclic group, and i, j and k are integers of 0 to 3 with the proviso that the sum of i, j and k is at least 1. Among this broad class, the 3-alkoxy propionate derivatives substituted in 2-position with bulky, preferably aromatic, rings are those more preferred. Their performances however, in terms of activity/stereospecificity balance seem not fully satisfactory.

SUMMARY OF THE INVENTION

It has been therefore very surprising to discover that a different class of alkoxypropionate derivatives is able to give catalyst showing an improved balance of high stereospecificity and high activity to make them eligible as replacement of phthalate donors.

Accordingly, an object of the present invention is a catalyst component for the polymerization of olefins comprising Mg, Ti and an electron donor compound of the following formula (I)

In which R to R₄ groups, equal to or different from each other, are hydrogen, halogen or C₁-C₁₅ hydrocarbon groups, optionally containing an heteroatom selected from halogen, P, S, N and Si, which may be linked to form a saturated or unsaturated mono or polycycle and R₅ groups are selected from C₁-C₁₅ hydrocarbon groups optionally containing an heteroatom selected from halogen, P, S, N and Si.

DETAILED DESCRIPTION OF THE INVENTION

Preferably R groups are selected from hydrogen and C₁-C₅ alkyl groups, such as methyl, ethyl, isopropyl, isobutyl and tert-butyl. Preferably, R groups are hydrogen.

Preferably, R₁ to R₄ groups are, independently, hydrogen or C₁-C₁₀ alkyl groups. More preferably R₁ to R₃ are hydrogen or C₁-C₁₀ alkyl groups and R₄ is a C₁-C₁₀ alkyl group. Compounds in which R₄ is selected from C₁-C₈ linear alkyl groups are especially preferred.

Preferably, R₅ groups are selected from C₁-C₁₀ alkyl groups and more preferably from C₁-C₆ alkyl groups. Among them, preferred are methyl, ethyl and isobutyl. In an especially preferred embodiment, R—R₃ groups are hydrogen, R₄ is selected from C₁-C₆ linear alkyl groups while R₅ is selected from C₁-C₄ alkyl groups.

Non limiting examples of structures (I) are the following: ethyl 3-(2-methoxyphenyl)propanoate, ethyl 2-(2-methoxybenzyl)-3,3-dimethylbutanoate, ethyl 2-(2-methoxybenzyl)-3-methylbutanoate, ethyl 2-(2-methoxybenzyl)-4-methylpentanoate, ethyl 2-(2-methoxybenzyl)butanoate, ethyl 2-(2-methoxybenzyl)hexanoate, ethyl 2-(2-methoxybenzyl)octanoate, ethyl 2-(2-methoxybenzyl)pentanoate, ethyl 2-benzyl-3-(2-methoxyphenyl)propanoate, ethyl 2-cyclohexyl-3-(2-methoxyphenyl)propanoate, ethyl 3-(2-methoxyphenyl)-2-methylpropanoate, ethyl 3-(2-methoxyphenyl)-2-phenylpropanoate, ethyl 2-(2-methoxybenzyl)-2,3,3-trimethylbutanoate, ethyl 2-(2-methoxybenzyl)-2,3-dimethylbutanoate, ethyl 2-(2-methoxybenzyl)-2,4-dimethylpentanoate, ethyl 2-(2-methoxybenzyl)-2-methylbutanoate, ethyl 2-(2-methoxybenzyl)-2-methylhexanoate, ethyl 2-(2-methoxybenzyl)-2-methyloctanoate, ethyl 2-(2-methoxybenzyl)-2-methylpentanoate, ethyl 2-(2-methoxybenzyl)-2-phenylbutanoate, ethyl 2-(2-methoxybenzyl)-2-phenylhexanoate, ethyl 2-(2-methoxybenzyl)-2-phenyloctanoate, ethyl 2-(2-methoxybenzyl)-2-phenylpentanoate, ethyl 2-(2-methoxybenzyl)-2-propylhexanoate, ethyl 2-(2-methoxybenzyl)-3,3-dimethyl-2-phenylbutanoate, ethyl 2-(2-methoxybenzyl)-3-methyl-2-phenylbutanoate, ethyl 2-(2-methoxybenzyl)-4-methyl-2-phenylpentanoate, ethyl 2-(2-methoxybenzyl)-4-methyl-2-propylpentanoate, ethyl 2-(tert-butyl)-2-(2-methoxybenzyl)-3,3-dimethylbutanoate, ethyl 2-(tert-butyl)-2-(2-methoxybenzyl)-4-methylpentanoate, ethyl 2-(tert-butyl)-2-(2-methoxybenzyl)hexanoate, ethyl 2-(tert-butyl)-2-(2-methoxybenzyl)octanoate, ethyl 2-(tert-butyl)-2-(2-methoxybenzyl)pentanoate, ethyl 2-benzyl-2-(2-methoxybenzyl)-3,3-dimethylbutanoate, ethyl 2-benzyl-2-(2-methoxybenzyl)-3-methylbutanoate, ethyl 2-benzyl-2-(2-methoxybenzyl)-4-methylpentanoate, ethyl 2-benzyl-2-(2-methoxybenzyl)butanoate, ethyl 2-benzyl-2-(2-methoxybenzyl)hexanoate, ethyl 2-benzyl-3-(2-methoxyphenyl)-2-methylpropanoate, ethyl 2-benzyl-3-(2-methoxyphenyl)-2-phenylpropanoate, ethyl 2-butyl-2-(2-methoxybenzyl)hexanoate, ethyl 2-butyl-2-(2-methoxybenzyl)octanoate, ethyl 2-cyclohexyl-2-(2-methoxybenzyl)-3,3-dimethylbutanoate, ethyl 2-cyclohexyl-2-(2-methoxybenzyl)-3-methylbutanoate, ethyl 2-cyclohexyl-2-(2-methoxybenzyl)-4-methylpentanoate, ethyl 2-cyclohexyl-2-(2-methoxybenzyl)butanoate, ethyl 2-cyclohexyl-2-(2-methoxybenzyl)hexanoate, ethyl 2-cyclohexyl-3-(2-methoxyphenyl)-2-methylpropanoate, ethyl 2-cyclohexyl-3-(2-methoxyphenyl)-2-phenylpropanoate, ethyl 2-ethyl-2-(2-methoxybenzyl)-3,3-dimethylbutanoate, ethyl 2-ethyl-2-(2-methoxybenzyl)-3-methylbutanoate, ethyl 2-ethyl-2-(2-methoxybenzyl)-4-methylpentanoate, ethyl 2-ethyl-2-(2-methoxybenzyl)butanoate, ethyl 2-ethyl-2-(2-methoxybenzyl)hexanoate, ethyl 2-ethyl-2-(2-methoxybenzyl)octanoate, ethyl 2-ethyl-2-(2-methoxybenzyl)pentanoate, ethyl 2-isobutyl-2-(2-methoxybenzyl)-4-methylpentanoate, ethyl 2-isobutyl-2-(2-methoxybenzyl)hexanoate, ethyl 2-isobutyl-2-(2-methoxybenzyl)octanoate, ethyl 2-isopropyl-2-(2-methoxybenzyl)-3,3-dimethylbutanoate, ethyl 2-isopropyl-2-(2-methoxybenzyl)-3-methylbutanoate, ethyl 2-isopropyl-2-(2-methoxybenzyl)-4-methylpentanoate, ethyl 2-isopropyl-2-(2-methoxybenzyl)hexanoate, ethyl 2-isopropyl-2-(2-methoxybenzyl)octanoate, ethyl 2-isopropyl-2-(2-methoxybenzyl)pentanoate, ethyl 3-(2-methoxyphenyl)-2,2-dimethylpropanoate, ethyl 3-(2-methoxyphenyl)-2-methyl-2-phenylpropanoate, ethyl 2-(1-(2-methoxyphenyl)-2,2-dimethylpropyl)hexanoate, ethyl 2-(1-(2-methoxyphenyl)-2-methylpropyl)hexanoate, ethyl 2-(1-(2-methoxyphenyl)-2-phenylethyl)-4-methylpentanoate, ethyl 2-(1-(2-methoxyphenyl)-2-phenylethyl)hexanoate, ethyl 2-(1-(2-methoxyphenyl)ethyl)-3,3-dimethylbutanoate, ethyl 2-(1-(2-methoxyphenyl)ethyl)-4-methylpentanoate, ethyl 2-(1-(2-methoxyphenyl)ethyl)hexanoate, ethyl 2-(tert-butyl)-3-(2-methoxyphenyl)-4,4-dimethylpentanoate, ethyl 2-(tert-butyl)-3-(2-methoxyphenyl)-4-methylpentanoate, ethyl 2-(tert-butyl)-3-(2-methoxyphenyl)-4-phenylbutanoate, ethyl 2-(tert-butyl)-3-(2-methoxyphenyl)-5-methylhexanoate, ethyl 2-(tert-butyl)-3-(2-methoxyphenyl)hexanoate, ethyl 2-butyl-3-(2-methoxyphenyl)-5-methylhexanoate, ethyl 2-butyl-3-(2-methoxyphenyl)hexanoate, ethyl 2-ethyl-3-(2-methoxyphenyl)-4,4-dimethylpentanoate, ethyl 2-ethyl-3-(2-methoxyphenyl)-4-methylpentanoate, ethyl 2-ethyl-3-(2-methoxyphenyl)-4-phenylbutanoate, ethyl 2-ethyl-3-(2-methoxyphenyl)-5-methylhexanoate, ethyl 2-ethyl-3-(2-methoxyphenyl)butanoate, ethyl 2-ethyl-3-(2-methoxyphenyl)hexanoate, ethyl 2-isobutyl-3-(2-methoxyphenyl)-4,4-dimethylpentanoate, ethyl 2-isobutyl-3-(2-methoxyphenyl)-4-methylpentanoate, ethyl 2-isobutyl-3-(2-methoxyphenyl)-5-methylhexanoate, ethyl 2-isobutyl-3-(2-methoxyphenyl)hexanoate, ethyl 2-isopropyl-3-(2-methoxyphenyl)-4,4-dimethylpentanoate, ethyl 2-isopropyl-3-(2-methoxyphenyl)-4-methylpentanoate, ethyl 2-isopropyl-3-(2-methoxyphenyl)-4-phenylbutanoate, ethyl 2-isopropyl-3-(2-methoxyphenyl)-5-methylhexanoate, ethyl 2-isopropyl-3-(2-methoxyphenyl)butanoate, ethyl 2-isopropyl-3-(2-methoxyphenyl)hexanoate, ethyl 3-(2-methoxyphenyl)-2,4,4-trimethylpentanoate, ethyl 3-(2-methoxyphenyl)-2,4-dimethylpentanoate, ethyl 3-(2-methoxyphenyl)-2,4-diphenylbutanoate, ethyl 3-(2-methoxyphenyl)-2,5-dimethylhexanoate, ethyl 3-(2-methoxyphenyl)-2-methyl-4-phenylbutanoate, ethyl 3-(2-methoxyphenyl)-2-methylbutanoate, ethyl 3-(2-methoxyphenyl)-2-methylhexanoate, ethyl 3-(2-methoxyphenyl)-2-phenylbutanoate, ethyl 3-(2-methoxyphenyl)-2-phenylhexanoate, ethyl 3-(2-methoxyphenyl)-4,4-dimethyl-2-phenylpentanoate, ethyl 3-(2-methoxyphenyl)-4-methyl-2-phenylpentanoate, ethyl 3-(2-methoxyphenyl)-5-methyl-2-phenylhexanoate, ethyl 2-(1-(2-methoxyphenyl)-2-phenylethyl)-2,4-dimethylpentanoate, ethyl 2-(1-(2-methoxyphenyl)ethyl)-2,3,3-trimethylbutanoate, ethyl 2-(1-(2-methoxyphenyl)ethyl)-2,4-dimethylpentanoate, ethyl 2-(tert-butyl)-2-(1-(2-methoxyphenyl)-2-phenylethyl)-4-methylpentanoate, ethyl 2-(tert-butyl)-2-(1-(2-methoxyphenyl)ethyl)-4-methylpentanoate, ethyl 2-(tert-butyl)-2-ethyl-3-(2-methoxyphenyl)-4-methylpentanoate, ethyl 2-(tert-butyl)-2-ethyl-3-(2-methoxyphenyl)-4-phenylbutanoate, ethyl 2-(tert-butyl)-2-ethyl-3-(2-methoxyphenyl)hexanoate, ethyl 2-(tert-butyl)-2-isobutyl-3-(2-methoxyphenyl)-4-methylpentanoate, ethyl 2-(tert-butyl)-2-isobutyl-3-(2-methoxyphenyl)hexanoate, ethyl 2-(tert-butyl)-3-(2-methoxyphenyl)-2,4-dimethylpentanoate, ethyl 2-(tert-butyl)-3-(2-methoxyphenyl)-2-methyl-4-phenylbutanoate, ethyl 2-(tert-butyl)-3-(2-methoxyphenyl)-2-methylhexanoate, ethyl 2-ethyl-2-(1-(2-methoxyphenyl)ethyl)-3,3-dimethylbutanoate, ethyl 2-ethyl-2-isopropyl-3-(2-methoxyphenyl)-4-methylpentanoate, ethyl 2-ethyl-2-isopropyl-3-(2-methoxyphenyl)-4-phenylbutanoate, ethyl 2-ethyl-2-isopropyl-3-(2-methoxyphenyl)butanoate, ethyl 2-ethyl-2-isopropyl-3-(2-methoxyphenyl)hexanoate, ethyl 2-ethyl-3-(2-methoxyphenyl)-2,4-dimethylpentanoate, ethyl 2-ethyl-3-(2-methoxyphenyl)-2-methyl-4-phenylbutanoate, ethyl 2-ethyl-3-(2-methoxyphenyl)-2-methylbutanoate, ethyl 2-ethyl-3-(2-methoxyphenyl)-2-methylhexanoate, ethyl 2-isobutyl-2-isopropyl-3-(2-methoxyphenyl)-4-methylpentanoate, ethyl 2-isobutyl-2-isopropyl-3-(2-methoxyphenyl)hexanoate, ethyl 2-isobutyl-3-(2-methoxyphenyl)-2,4-dimethylpentanoate, ethyl 2-isobutyl-3-(2-methoxyphenyl)-2-methylhexanoate, ethyl 2-isopropyl-2-(1-(2-methoxyphenyl)-2-phenylethyl)-4-methylpentanoate, ethyl 2-isopropyl-2-(1-(2-methoxyphenyl)ethyl)-4-methylpentanoate, ethyl 2-isopropyl-3-(2-methoxyphenyl)-2,4-dimethylpentanoate, ethyl 2-isopropyl-3-(2-methoxyphenyl)-2-methyl-4-phenylbutanoate, ethyl 2-isopropyl-3-(2-methoxyphenyl)-2-methylbutanoate, ethyl 2-isopropyl-3-(2-methoxyphenyl)-2-methylhexanoate, ethyl 3-(2-methoxyphenyl)-2,2,4-trimethylpentanoate, ethyl 3-(2-methoxyphenyl)-2,2-dimethyl-4-phenylbutanoate, ethyl 3-(2-methoxyphenyl)-2,2-dimethylbutanoate, ethyl 3-(2-methoxyphenyl)-2,2-dimethylhexanoate, ethyl 2-(2-(2-methoxyphenyl)-1-phenylpropan-2-yl)-2,4-dimethylpentanoate, ethyl 2-(2-(2-methoxyphenyl)propan-2-yl)-2,4-dimethylpentanoate, ethyl 2-(tert-butyl)-2-(2-(2-methoxyphenyl)-1-phenylpropan-2-yl)-4-methylpentanoate, ethyl 2-(tert-butyl)-2-(2-(2-methoxyphenyl)propan-2-yl)-4-methylpentanoate, ethyl 2-(tert-butyl)-2-isobutyl-3-(2-methoxyphenyl)-3,4-dimethylpentanoate, ethyl 2-(tert-butyl)-2-isobutyl-3-(2-methoxyphenyl)-3-methylpentanoate, ethyl 2-(tert-butyl)-3-(2-methoxyphenyl)-2,3,4-trimethylpentanoate, ethyl 2-(tert-butyl)-3-(2-methoxyphenyl)-2,3-dimethyl-4-phenylbutanoate, ethyl 2-(tert-butyl)-3-(2-methoxyphenyl)-2,3-dimethylbutanoate, ethyl 2-(tert-butyl)-3-(2-methoxyphenyl)-2,3-dimethylpentanoate, ethyl 2-(tert-butyl)-3-ethyl-2-isobutyl-3-(2-methoxyphenyl)-4-methylpentanoate, ethyl 2-(tert-butyl)-3-ethyl-3-(2-methoxyphenyl)-2,4-dimethylpentanoate, ethyl 2-isobutyl-2-isopropyl-3-(2-methoxyphenyl)-3,4-dimethylpentanoate, ethyl 2-isobutyl-2-isopropyl-3-(2-methoxyphenyl)-3-methylpentanoate, ethyl 2-isobutyl-3-(2-methoxyphenyl)-2,3,4-trimethylpentanoate, ethyl 2-isobutyl-3-(2-methoxyphenyl)-2,3-dimethylpentanoate, ethyl 2-isopropyl-2-(2-(2-methoxyphenyl)-1-phenylpropan-2-yl)-4-methylpentanoate, ethyl 2-isopropyl-2-(2-(2-methoxyphenyl)propan-2-yl)-4-methylpentanoate, ethyl 2-isopropyl-3-(2-methoxyphenyl)-2,3,4-trimethylpentanoate, ethyl 2-isopropyl-3-(2-methoxyphenyl)-2,3-dimethyl-4-phenylbutanoate, ethyl 2-isopropyl-3-(2-methoxyphenyl)-2,3-dimethylbutanoate, ethyl 2-isopropyl-3-(2-methoxyphenyl)-2,3-dimethylpentanoate, ethyl 3-(2-methoxyphenyl)-2,2,3,4-tetramethylpentanoate, ethyl 3-(2-methoxyphenyl)-2,2,3-trimethyl-4-phenylbutanoate, ethyl 3-(2-methoxyphenyl)-2,2,3-trimethylbutanoate, ethyl 3-(2-methoxyphenyl)-2,2,3-trimethylpentanoate, ethyl 3-benzyl-2-(tert-butyl)-2-isobutyl-3-(2-methoxyphenyl)pentanoate, ethyl 3-benzyl-2-(tert-butyl)-3-(2-methoxyphenyl)-2-methylpentanoate, ethyl 3-benzyl-2-isobutyl-2-isopropyl-3-(2-methoxyphenyl)pentanoate, ethyl 3-benzyl-2-isobutyl-3-(2-methoxyphenyl)-2-methylpentanoate, ethyl 3-benzyl-2-isopropyl-3-(2-methoxyphenyl)-2-methylpentanoate, ethyl 3-benzyl-3-(2-methoxyphenyl)-2,2-dimethylpentanoate, ethyl 3-ethyl-2-isobutyl-2-isopropyl-3-(2-methoxyphenyl)-4-methylpentanoate, ethyl 3-ethyl-2-isobutyl-3-(2-methoxyphenyl)-2,4-dimethylpentanoate, ethyl 3-ethyl-2-isopropyl-3-(2-methoxyphenyl)-2,4-dimethylpentanoate, ethyl 3-ethyl-3-(2-methoxyphenyl)-2,2,4-trimethylpentanoate, ethyl 2-(2-methoxy-3,5-dimethylbenzyl)-4-methylpentanoate, ethyl 2-(2-methoxy-3-methylbenzyl)-4-methylpentanoate, ethyl 2-(2-methoxy-5-methylbenzyl)-4-methylpentanoate, ethyl 2-(2-methoxybenzyl)-4-methylpentanoate, ethyl 2-(3,5-di-tert-butyl-2-methoxybenzyl)-4-methylpentanoate, ethyl 2-(3,5-diisopropyl-2-methoxybenzyl)-4-methylpentanoate, ethyl 2-(3-(tert-butyl)-2-methoxy-5-methylbenzyl)-4-methylpentanoate, ethyl 2-(3-(tert-butyl)-2-methoxybenzyl)-4-methylpentanoate, ethyl 2-(3-(tert-butyl)-5-isopropyl-2-methoxybenzyl)-4-methylpentanoate, ethyl 2-(3-isopropyl-2-methoxy-5-methylbenzyl)-4-methylpentanoate, ethyl 2-(3-isopropyl-2-methoxybenzyl)-4-methylpentanoate, ethyl 2-(5-(tert-butyl)-2-methoxy-3-methylbenzyl)-4-methylpentanoate, ethyl 2-(5-(tert-butyl)-2-methoxybenzyl)-4-methylpentanoate, ethyl 2-(5-(tert-butyl)-3-isopropyl-2-methoxybenzyl)-4-methylpentanoate, ethyl 2-(5-isopropyl-2-methoxy-3-methylbenzyl)-4-methylpentanoate, ethyl 2-(5-isopropyl-2-methoxybenzyl)-4-methylpentanoate, ethyl 3-(2-methoxy-3,5-dimethylphenyl)-2-methylpropanoate, ethyl 3-(2-methoxy-3-methylphenyl)-2-methylpropanoate, ethyl 3-(2-methoxy-5-methylphenyl)-2-methylpropanoate, ethyl 3-(2-methoxyphenyl)-2-methylpropanoate, ethyl 3-(3,5-di-tert-butyl-2-methoxyphenyl)-2-methylpropanoate, ethyl 3-(3,5-diisopropyl-2-methoxyphenyl)-2-methylpropanoate, ethyl 3-(3-(tert-butyl)-2-methoxy-5-methylphenyl)-2-methylpropanoate, ethyl 3-(3-(tert-butyl)-2-methoxyphenyl)-2-methylpropanoate, ethyl 3-(3-(tert-butyl)-5-isopropyl-2-methoxyphenyl)-2-methylpropanoate, ethyl 3-(3-isopropyl-2-methoxy-5-methylphenyl)-2-methylpropanoate, ethyl 3-(3-isopropyl-2-methoxyphenyl)-2-methylpropanoate, ethyl 3-(5-(tert-butyl)-2-methoxy-3-methylphenyl)-2-methylpropanoate, ethyl 3-(5-(tert-butyl)-2-methoxyphenyl)-2-methylpropanoate, ethyl 3-(5-(tert-butyl)-3-isopropyl-2-methoxyphenyl)-2-methylpropanoate, ethyl 3-(5-isopropyl-2-methoxy-3-methylphenyl)-2-methylpropanoate, ethyl 3-(5-isopropyl-2-methoxyphenyl)-2-methylpropanoate, ethyl 3-(2-methoxy-3,5-dimethylphenyl)propanoate, ethyl 3-(2-methoxy-3-methylphenyl)propanoate, ethyl 3-(2-methoxy-5-methylphenyl)propanoate, ethyl 3-(3,5-di-tert-butyl-2-methoxyphenyl)propanoate, ethyl 3-(3-(tert-butyl)-2-methoxy-5-methylphenyl)propanoate, ethyl 3-(3-(tert-butyl)-2-methoxyphenyl)propanoate, ethyl 3-(5-(tert-butyl)-2-methoxy-3-methylphenyl)propanoate, ethyl 3-(5-(tert-butyl)-2-methoxyphenyl)propanoate, ethyl 3-(3,5-diisopropyl-2-methoxyphenyl)propanoate, butyl 2-(2-methoxybenzyl)-4-methylpentanoate, butyl 3-(2-methoxyphenyl)-2-methylpropanoate, isobutyl 2-(2-methoxybenzyl)-4-methylpentanoate, isobutyl 3-(2-methoxyphenyl)-2-methylpropanoate, methyl 2-(2-methoxybenzyl)-4-methylpentanoate, methyl 3-(2-methoxyphenyl)-2-methylpropanoate, ethyl 4-ethyl-2-(2-methoxybenzyl)hexanoate, ethyl 4-ethyl-2-(2-methoxybenzyl)octanoate

As explained above, the catalyst components of the invention comprise, in addition to the above electron donors, Ti, Mg and halogen. In particular, the catalyst components comprise a titanium compound, having at least a Ti-halogen bond and the above mentioned electron donor compounds supported on a Mg halide. The magnesium halide is preferably MgCl₂ in active form which is widely known from the patent literature as a support for Ziegler-Natta catalysts. U.S. Pat. No. 4,298,718 and U.S. Pat. No. 4,495,338 were the first to describe the use of these compounds in Ziegler-Natta catalysis. It is known from these patents that the magnesium dihalides in active form used as support or co-support in components of catalysts for the polymerization of olefins are characterized by X-ray spectra in which the most intense diffraction line that appears in the spectrum of the non-active halide is diminished in intensity and is replaced by a halo whose maximum intensity is displaced towards lower angles relative to that of the more intense line.

The preferred titanium compounds used in the catalyst of the present invention are TiCl₄ and TiCl₃; furthermore, also Ti-haloalcoholates of formula Ti(OR)_(q-y)X_(y) can be used, where q is the valence of titanium, y is a number between 1 and q−1, X is halogen and R is a hydrocarbon radical having from 1 to 10 carbon atoms.

The preparation of the solid catalyst component can be carried out according to several methods.

According to one of these methods, the magnesium dichloride in an anhydrous state, the titanium compound and the electron donor compounds are milled together under conditions in which activation of the magnesium dichloride occurs. The so obtained product can be treated one or more times with an excess of TiCl₄ at a temperature between 80 and 135° C. This treatment is followed by washings with hydrocarbon solvents until chloride ions disappeared. According to a further method, the product obtained by co-milling the magnesium chloride in an anhydrous state, the titanium compound and the electron donor compounds are treated with halogenated hydrocarbons such as 1,2-dichloroethane, chlorobenzene, dichloromethane etc. The treatment is carried out for a time between 1 and 4 hours and at temperature of from 40° C. to the boiling point of the halogenated hydrocarbon. Another method comprises the reaction between magnesium alcoholates or chloroalcoholates (in particular chloroalcoholates prepared according to U.S. Pat. No. 4,220,554) and an excess of TiCl₄ in the presence of the electron donor compounds at a temperature of about 80 to 120° C.

According to a preferred method, the solid catalyst component can be prepared by reacting a titanium compound of formula Ti(OR)_(q-y)X_(y), where q is the valence of titanium and y is a number between 1 and q, preferably TiCl₄, with a magnesium chloride deriving from an adduct of formula MgCl₂.pROH, where p is a number between 0.1 and 6, preferably from 2 to 3.5, and R is a hydrocarbon radical having 1-18 carbon atoms. The adduct can be suitably prepared in spherical form by mixing alcohol and magnesium chloride in the presence of an inert hydrocarbon immiscible with the adduct, operating under stirring conditions at the melting temperature of the adduct (100-130° C.). Then, the emulsion is quickly quenched, thereby causing the solidification of the adduct in form of spherical particles. Examples of spherical adducts prepared according to this procedure are described in U.S. Pat. No. 4,399,054 and U.S. Pat. No. 4,469,648. The so obtained adduct can be directly reacted with Ti compound or it can be previously subjected to thermal controlled dealcoholation (80-130° C.) so as to obtain an adduct in which the number of moles of alcohol is generally lower than 3, preferably between 0.1 and 2.5. The reaction with the Ti compound can be carried out by suspending the adduct (dealcoholated or as such) in cold TiCl₄ (generally 0° C.); the mixture is heated up to 80-130° C. and kept at this temperature for 0.5-2 hours. The treatment with TiCl₄ can be carried out one or more times. The electron donor compounds can be added in the desired ratios during the treatment with TiCl₄. The preparation of catalyst components in spherical form are described for example in European Patent Applications EP-A-395083, EP-A-553805, EP-A-553806, EPA601525 and WO98/44001.

The solid catalyst components obtained according to the above method show a surface area (by B.E.T. method) generally between 20 and 500 m²/g and preferably between 50 and 400 m²/g, and a total porosity (by B.E.T. method) higher than 0.2 cm³/g preferably between 0.2 and 0.6 cm³/g. The porosity (Hg method) due to pores with radius up to 10.000 Å generally ranges from 0.3 to 1.5 cm³/g, preferably from 0.45 to 1 cm³/g.

The solid catalyst component has an average particle size ranging from 5 to 120 μm and more preferably from 10 to 100 p.m.

As mentioned, in any of these preparation methods the desired electron donor compounds can be added as such or, in an alternative way, can be obtained in situ by using an appropriate precursor capable of being transformed in the desired electron donor compound by means, for example, of known chemical reactions such as etherification, alkylation, esterification, transesterification etc.

Regardless of the preparation method used, the final amount of the electron donor compound of formula (I) is such that its molar ratio with respect to the Ti atoms is from 0.01 to 3, preferably from 0.1 to 2, more preferably from 0.2 to 1.5.

The solid catalyst components according to the present invention are converted into catalysts for the polymerization of olefins by reacting them with organoaluminum compounds according to known methods.

In particular, an object of the present invention is a catalyst for the polymerization of olefins CH₂═CHR, in which R is hydrogen or a hydrocarbyl radical with 1-12 carbon atoms, comprising the product obtained by contacting:

(i) the solid catalyst component as disclosed above and

(ii) an alkylaluminum compound and

(iii) optionally an external electron donor compound.

The alkyl-Al compound (ii) is preferably chosen among the trialkyl aluminum compounds such as for example triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum. It is also possible to use alkylaluminum halides, alkylaluminum hydrides or alkylaluminum sesquichlorides, such as AlEt₂Cl and Al₂Et₃Cl₃, possibly in mixture with the above cited trialkylaluminums.

Suitable external electron-donor compounds (iii) include silicon compounds, ethers, esters, amines, heterocyclic compounds and particularly 2,2,6,6-tetramethylpiperidine and ketones.

Another class of preferred external donor compounds is that of silicon compounds of formula (R₆)_(a)(R₂)_(b)Si(OR₈)_(c), where a and b are integers from 0 to 2, c is an integer from 1 to 4 and the sum (a+b+c) is 4; R₆, R₇, and R₈, are alkyl, cycloalkyl or aryl radicals with 1-18 carbon atoms optionally containing heteroatoms. Particularly preferred are the silicon compounds in which a is 1, b is 1, c is 2, at least one of R₆ and R₇ is selected from branched alkyl, cycloalkyl or aryl groups with 3-10 carbon atoms optionally containing heteroatoms and R₈ is a C₁-C₁₀ alkyl group, in particular methyl. Examples of such preferred silicon compounds are methylcyclohexyldimethoxysilane, diphenyldimethoxysilane, diisopropyldimethoxysilane, methyl-t-butyldimethoxysilane, dicyclopentyldimethoxysilane (D donor), (2-ethylpiperidinyl)t-butyldimethoxysilane, (2-ethylpiperidinyl)thexyldimethoxysilane, (3,3,3-trifluoro-n-propyl)(2-ethylpiperidinyl)dimethoxysilane, methyl(3,3,3-trifluoro-n-propyl)dimethoxysilane. Moreover, the silicon compounds in which a is 0, c is 3, R₇ is a branched alkyl or cycloalkyl group, optionally containing heteroatoms, and R₈ is methyl are also preferred. Examples of such preferred silicon compounds are cyclohexyltrimethoxysilane, t-butyltrimethoxysilane and thexyltrimethoxysilane.

The electron donor compound (iii) is used in such an amount to give a molar ratio between the organoaluminum compound and said electron donor compound (iii) of from 0.1 to 500, preferably from 1 to 300 and more preferably from 3 to 100.

Therefore, it constitutes a further object of the present invention a process for the (co)polymerization of olefins CH₂═CHR, in which R is hydrogen or a hydrocarbyl radical with 1-12 carbon atoms, carried out in the presence of a catalyst comprising the product of the reaction between:

(i) the solid catalyst of the invention;

(ii) an alkylaluminum compound and,

(iii) optionally an electron-donor compound (external donor).

The polymerization process can be carried out according to known techniques for example slurry polymerization using as diluent an inert hydrocarbon solvent, or bulk polymerization using the liquid monomer (for example propylene) as a reaction medium. Moreover, it is possible to carry out the polymerization process in gas-phase operating in one or more fluidized or mechanically agitated bed reactors.

The polymerization is generally carried out at temperature of from 20 to 120° C., preferably of from 40 to 80° C. When the polymerization is carried out in gas-phase the operating pressure is generally between 0.5 and 5 MPa, preferably between 1 and 4 MPa. In the bulk polymerization the operating pressure is generally between 1 and 8 MPa, preferably between 1.5 and 5 MPa.

The following examples are given in order to better illustrate the invention without limiting it.

EXAMPLES Characterizations

Determination of Ti

The determination of Ti content in the solid catalyst component has been carried out via inductively coupled plasma emission spectroscopy on “I.C.P Spectrometer ARL Accuris”.

The sample was prepared by analytically weighting, in a “fluxy” platinum crucible”, 0.1÷0.3 grams of catalyst and 3 grams of lithium metaborate/tetraborate 1/1 mixture. The crucible is placed on a weak Bunsen flame for the burning step and then after addition of some drops of KI solution inserted in a special apparatus “Claisse Fluxy” for the complete burning. The residue is collected with a 5% v/v HNO₃ solution and then the titanium was analyzed via ICP at a wavelength of 368.52 nm

Determination of Internal Donor Content

The determination of the content of internal donor in the solid catalytic compound was done through gas chromatography. The solid component was dissolved in acidic water. The solution was extracted with ethyl acetate, an internal standard was added, and a sample of the organic phase was analyzed in a gas chromatograph, to determine the amount of donor present at the starting catalyst compound.

Determination of X.I.

2.5 g of polymer and 250 ml of o-xylene were placed in a round-bottomed flask provided with a cooler and a reflux condenser and kept under nitrogen. The obtained mixture was heated to 135° C. and was kept under stirring for about 60 minutes. The final solution was allowed to cool to 25° C. under continuous stirring, and the insoluble polymer was then filtered. The filtrate was then evaporated in a nitrogen flow at 140° C. to reach a constant weight. The content of said xylene-soluble fraction is expressed as a percentage of the original 2.5 grams and then, by difference, the X.I. %.

Melt Flow Rate (MFR)

The melt flow rate MIL of the polymer was determined according to ISO 1133 (230° C., 2.16 Kg)

Procedure for Preparation of the Spherical Adduct

An initial amount of microspheroidal MgCl₂.2.8C₂H₅OH was prepared according to the method described in Example 2 of WO98/44009, but operating on larger scale. The support adduct had a P50 of about 25 micron, and an ethanol content of about 56% wt.

General Procedure for the Preparation of the Solid Catalyst Component

Into a 500 ml round bottom flask, equipped with mechanical stirrer, cooler and thermometer 250 ml of TiCl₄ were introduced at room temperature under nitrogen atmosphere. After cooling to 0° C., while stirring, the internal donor and 10.0 g of the spherical adduct (prepared as described above) were sequentially added into the flask. The amount of charged internal donor was such to charge a Mg/donor molar ratio of 6. The temperature was raised to 100° C. and maintained for 2 hours. Thereafter, stirring was stopped, the solid product was allowed to settle and the supernatant liquid was siphoned off at 100° C. After the supernatant was removed, additional fresh TiCl4 was added to reach the initial liquid volume again. The mixture was then heated at 120° C. and kept at this temperature for 1 hour. Stirring was stopped again, the solid was allowed to settle and the supernatant liquid was siphoned off.

The solid was washed with anhydrous hexane six times (6×100 ml) in temperature gradient down to 60° C. and one time (100 ml) at room temperature. The obtained solid was then dried under vacuum and analyzed. The measured composition of the solid is depicted in Table 1.

General Procedure for the Polymerization of Propylene

A 4-liter steel autoclave equipped with a stirrer, pressure gauge, thermometer, catalyst feeding system, monomer feeding lines and thermostating jacket, was purged with nitrogen flow at 70° C. for one hour. Then, at 30° C. under propylene flow, were charged in sequence with 75 ml of anhydrous hexane, 0.76 g of AlEt₃, 0.076 g of dicyclopentyldimethoxysilane (D donor) and 0.006÷0.010 g of solid catalyst component. The autoclave was closed; subsequently 2.0 NL of hydrogen were added. Then, under stirring, 1.2 kg of liquid propylene was fed. The temperature was raised to 70° C. in five minutes and the polymerization was carried out at this temperature for two hours. At the end of the polymerization, the non-reacted propylene was removed; the polymer was recovered and dried at 70° C. under vacuum for three hours. Then the polymer was weighed and fractionated with o-xylene to determine the amount of the xylene insoluble (X.I.) fraction.

Examples 1-15, and Comparative Examples 1-2

Various donors were used in the preparation of the solid catalyst component, following the description given above. The donors used are listed in Table 1.

The thus obtained solid catalyst components were analyzed for their composition, and in polymerization, using the method described above. The titanium and donor content of the catalyst components, and their performance in polymerization are also shown in Table 1.

TABLE 1 Composition and performance of exemplified catalysts Internal donor % Ti Mileage XI MIL Ex. Name wt wt % kg/g wt % g/10′ 1 ethyl 2-(2-methoxybenzyl)-3-methylbutanoate 9.9 4.6 57 95.5 3.9 2 ethyl 2-(2-methoxybenzyl)-4-methylpentanoate 9.8 5.3 65 96.3 3.1 3 ethyl 3-(2-methoxyphenyl)-2-methylpropanoate 8.3 3.9 43 96.9 3.8 4 ethyl 3-(2-methoxyphenyl)-2,2-dimethylpropanoate 7.1 ND 52 96.0 3.2 5 ethyl 2-benzyl-3-(2-methoxyphenyl)propanoate 10.3 4.8 71 96.3 0.7 6 isobutyl 2-(2-methoxybenzyl)-4-methylpentanoate 9.6 5.4 64 95.8 2.7 7 ethyl 2-(2-methoxy-5-methylbenzyl)-4-methylpentanoate 10.2 4.8 50 95.7 4.1 8 ethyl 3-(2-methoxyphenyl)propanoate 5.2 3.7 35 96.0 3.3 9 ethyl 3-(2-methoxyphenyl)butanoate 21.8 4.4 59 97.5 2.9 10 ethyl 3-(2-methoxyphenyl)-2-methylbutanoate ND 4.8 58 97.2 2.9 11 ethyl 3-(2-methoxyphenyl)-5-methylhexanoate 16.6 4.0 60 97.4 4.7 12 ethyl 3-(2-methoxyphenyl)-4-methylhexanoate 18.1 4.6 52 97.6 8.2 13 ethyl 3-(2-methoxyphenyl)heptanoate 11.7 4.2 45 97.3 5.9 14 ethyl 3-(5-chloro-2-methoxyphenyl)butanoate 18.7 4.4 67 96.8 3.5 15 ethyl 3-(2-methoxy-4-methylphenyl)butanoate 11.2 4.1 64 97.4 3.5 C1 ethyl 2-benzyl-4-methylpentanoate 5.8 2.1 59 93.3 6.4 C2 ethyl 2-(2-methoxyphenyl)-3-phenylpropanoate N.D. 4.7 44 94.5 4.6 N.D. no data 

What is claimed is:
 1. A catalyst comprising: a solid catalyst component comprising Mg, Ti and an electron donor compound of the following formula (I)

in which R to R₄ groups, equal to or different from each other, are hydrogen, halogen or C₁-C₁₅ hydrocarbon groups, optionally containing a heteroatom selected from halogen, P, S, N and Si, wherein the R to R₄ groups may be linked to form a saturated or unsaturated mono or polycycle and R₅ groups are selected from C₁-C₁₅ hydrocarbon groups optionally containing a heteroatom selected from halogen, P, S, N and Si.
 2. The catalyst of claim 1 in which R groups are selected from hydrogen or C₁-C₅ alkyl groups.
 3. The catalyst of claim 2 in which R groups are hydrogen.
 4. The catalyst of claim 1 in which R₁ to R₄ groups are, independently, hydrogen or C₁-C₁₀ alkyl groups.
 5. The catalyst of claim 4 in which R₁ to R₃ are hydrogen or C₁-C₁₀ alkyl groups and R₄ is a C₁-C₁₀ alkyl group.
 6. The catalyst of claim 5 in which R₁ to R₃ groups are hydrogen.
 7. The catalyst of claim 5 in which R₄ is selected from C₁-C₈ linear alkyl groups.
 8. The catalyst of claim 1 in which R₅ groups are selected from C₁-C₁₀ alkyl groups.
 9. The catalyst of claim 1 in which R₅ groups are selected from C₁-C₆ alkyl groups.
 10. The catalyst of claim 1 comprising the product obtained by contacting: the solid catalyst component; an alkylaluminum compound and optionally, an external electron-donor compound.
 11. A process for the (co)polymerization of olefins carried out in the presence of the catalyst according to claim
 10. 